1//===-- TypeFinder.cpp - Implement the TypeFinder class -------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the TypeFinder class for the IR library.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/IR/TypeFinder.h"
15#include "llvm/ADT/SmallVector.h"
16#include "llvm/IR/BasicBlock.h"
17#include "llvm/IR/DerivedTypes.h"
18#include "llvm/IR/Function.h"
19#include "llvm/IR/Metadata.h"
20#include "llvm/IR/Module.h"
21using namespace llvm;
22
23void TypeFinder::run(const Module &M, bool onlyNamed) {
24  OnlyNamed = onlyNamed;
25
26  // Get types from global variables.
27  for (Module::const_global_iterator I = M.global_begin(),
28         E = M.global_end(); I != E; ++I) {
29    incorporateType(I->getType());
30    if (I->hasInitializer())
31      incorporateValue(I->getInitializer());
32  }
33
34  // Get types from aliases.
35  for (Module::const_alias_iterator I = M.alias_begin(),
36         E = M.alias_end(); I != E; ++I) {
37    incorporateType(I->getType());
38    if (const Value *Aliasee = I->getAliasee())
39      incorporateValue(Aliasee);
40  }
41
42  // Get types from functions.
43  SmallVector<std::pair<unsigned, MDNode *>, 4> MDForInst;
44  for (const Function &FI : M) {
45    incorporateType(FI.getType());
46
47    for (const Use &U : FI.operands())
48      incorporateValue(U.get());
49
50    // First incorporate the arguments.
51    for (Function::const_arg_iterator AI = FI.arg_begin(), AE = FI.arg_end();
52         AI != AE; ++AI)
53      incorporateValue(&*AI);
54
55    for (const BasicBlock &BB : FI)
56      for (const Instruction &I : BB) {
57        // Incorporate the type of the instruction.
58        incorporateType(I.getType());
59
60        // Incorporate non-instruction operand types. (We are incorporating all
61        // instructions with this loop.)
62        for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
63             OI != OE; ++OI)
64          if (*OI && !isa<Instruction>(OI))
65            incorporateValue(*OI);
66
67        // Incorporate types hiding in metadata.
68        I.getAllMetadataOtherThanDebugLoc(MDForInst);
69        for (unsigned i = 0, e = MDForInst.size(); i != e; ++i)
70          incorporateMDNode(MDForInst[i].second);
71
72        MDForInst.clear();
73      }
74  }
75
76  for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
77         E = M.named_metadata_end(); I != E; ++I) {
78    const NamedMDNode *NMD = &*I;
79    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
80      incorporateMDNode(NMD->getOperand(i));
81  }
82}
83
84void TypeFinder::clear() {
85  VisitedConstants.clear();
86  VisitedTypes.clear();
87  StructTypes.clear();
88}
89
90/// incorporateType - This method adds the type to the list of used structures
91/// if it's not in there already.
92void TypeFinder::incorporateType(Type *Ty) {
93  // Check to see if we've already visited this type.
94  if (!VisitedTypes.insert(Ty).second)
95    return;
96
97  SmallVector<Type *, 4> TypeWorklist;
98  TypeWorklist.push_back(Ty);
99  do {
100    Ty = TypeWorklist.pop_back_val();
101
102    // If this is a structure or opaque type, add a name for the type.
103    if (StructType *STy = dyn_cast<StructType>(Ty))
104      if (!OnlyNamed || STy->hasName())
105        StructTypes.push_back(STy);
106
107    // Add all unvisited subtypes to worklist for processing
108    for (Type::subtype_reverse_iterator I = Ty->subtype_rbegin(),
109                                        E = Ty->subtype_rend();
110         I != E; ++I)
111      if (VisitedTypes.insert(*I).second)
112        TypeWorklist.push_back(*I);
113  } while (!TypeWorklist.empty());
114}
115
116/// incorporateValue - This method is used to walk operand lists finding types
117/// hiding in constant expressions and other operands that won't be walked in
118/// other ways.  GlobalValues, basic blocks, instructions, and inst operands are
119/// all explicitly enumerated.
120void TypeFinder::incorporateValue(const Value *V) {
121  if (const auto *M = dyn_cast<MetadataAsValue>(V)) {
122    if (const auto *N = dyn_cast<MDNode>(M->getMetadata()))
123      return incorporateMDNode(N);
124    if (const auto *MDV = dyn_cast<ValueAsMetadata>(M->getMetadata()))
125      return incorporateValue(MDV->getValue());
126    return;
127  }
128
129  if (!isa<Constant>(V) || isa<GlobalValue>(V)) return;
130
131  // Already visited?
132  if (!VisitedConstants.insert(V).second)
133    return;
134
135  // Check this type.
136  incorporateType(V->getType());
137
138  // If this is an instruction, we incorporate it separately.
139  if (isa<Instruction>(V))
140    return;
141
142  // Look in operands for types.
143  const User *U = cast<User>(V);
144  for (Constant::const_op_iterator I = U->op_begin(),
145         E = U->op_end(); I != E;++I)
146    incorporateValue(*I);
147}
148
149/// incorporateMDNode - This method is used to walk the operands of an MDNode to
150/// find types hiding within.
151void TypeFinder::incorporateMDNode(const MDNode *V) {
152  // Already visited?
153  if (!VisitedMetadata.insert(V).second)
154    return;
155
156  // Look in operands for types.
157  for (unsigned i = 0, e = V->getNumOperands(); i != e; ++i) {
158    Metadata *Op = V->getOperand(i);
159    if (!Op)
160      continue;
161    if (auto *N = dyn_cast<MDNode>(Op)) {
162      incorporateMDNode(N);
163      continue;
164    }
165    if (auto *C = dyn_cast<ConstantAsMetadata>(Op)) {
166      incorporateValue(C->getValue());
167      continue;
168    }
169  }
170}
171